That's a question -- or complaint, really -- that we get a lot. Consumers often aren't pleased with insurers asking for social security numbers to run insurance quotes.
Here's often why they do it: Your social security number is a key tool to quickly pull up your credit data, which is commonly used to quickly rate you as a risk and determine the rates you would pay for, say, auto insurance. (While Washington State Insurance Commissioner has repeatedly tried to ban this controversial practice, known as "credit scoring," there's nothing in Washington state or federal law to prohibit use of social security numbers by insurers.)
In other cases, however, insurers are actually required to collect it. Federal law requires many health insurers to report social security numbers in order for Medicare to properly coordinate Medicare payments with other insurance and workers' compensation benefits.